prevent NRE"s

Author: mythz

src/ServiceStack.Text/Common/DeserializeDictionary.cs

@@ -102,6 +102,9 @@ public static JsonObject ParseJsonObject(string value)
 
         public static Dictionary<string, string> ParseStringDictionary(string value)
         {
+            if (value == null) 
+                return null;
+
             var index = VerifyAndGetStartIndex(value, typeof(Dictionary<string, string>));
 
             var result = new Dictionary<string, string>();

src/ServiceStack.Text/PclExport.Net40.cs

@@ -1058,6 +1058,9 @@ private static int VerifyAndGetStartIndex(string value, Type createMapType)
 
         public static Hashtable ParseHashtable(string value)
         {
+            if (value == null) 
+                return null;
+
             var index = VerifyAndGetStartIndex(value, typeof(Hashtable));
 
             var result = new Hashtable();